Yes,
surely the only possibly reason for an organisation not doing
something that it technically possibly could is "gross incompetence"...
"Technically possibly could", and
committed to doing by bidding for Oval, you mean?
Quite. As I imagine @Adam Williams knows only too well from his work in another domain (similar but not the same), matters aren't always necessarily quite as simple or straightforward as one might initially think. Dare I suggest that such a blanket statement from such an esteemed poster as himself is perhaps a little unbecoming...?
I'm happy to evaluate technical arguments as to why it's not as simple as I've described. Indeed, I can think of a few limitations with what I've proposed (mostly around obscure Railcards), but it'd be a start that worked for a good majority of passengers which is what the aim should be, at least initially. I think it's fair to ask why no progress has been made when substantial amounts of public money are going towards this organisation. It's not just Railcards, there was a period where staff weren't able to get the discount flag set on their Oyster cards properly either. It's poor. There are non-technical factors for sure, but I'd argue some of these non-technical factors are also indicative of questionable historical procurement practice.
I'm pretty tired of seeing TfL lauded as some sort of uniquely innovative authority that blessed us with Oyster 22 years ago and contactless 13 years ago so we can't criticise them or identify clear opportunities for long overdue improvements anymore. Londoners and passengers transiting London deserve better than that.
It's not just discount associations or mobile coverage either, it's the information security issues (including getting pwned by a 17 year old kid, continuing to use SMS-based multifactor auth when established security best practice has considered it harmful for the best part of a decade) as well.